获取设备的mac地址可靠的方法

　　/**
     * 获取设备的mac地址
     * 
     * @param ac
     * @param callback
     *            成功获取到mac地址之后会回调此方法
     */ 
    public static void getMacAddress(final Activity ac, final SimpleCallback callback) { 
        final WifiManager wm = (WifiManager) ac .getSystemService(Service.WIFI_SERVICE); 
   
        // 如果本次开机后打开过WIFI，则能够直接获取到mac信息。立刻返回数据。 
        WifiInfo info = wm.getConnectionInfo(); 
        if (info != null && info.getMacAddress() != null) { 
            if (callback != null) { 
                callback.onComplete(info.getMacAddress()); 
            } 
            return; 
        } 
   
        // 尝试打开WIFI，并获取mac地址 
        if (!wm.isWifiEnabled()) { 
            wm.setWifiEnabled(true); 
        } 
   
        new Thread(new Runnable() { 
            @Override 
            public void run() { 
                int tryCount = 0; 
                final int MAX_COUNT = 10; 
   
                while (tryCount < MAX_COUNT) { 
                    final WifiInfo info = wm.getConnectionInfo(); 
                    if (info != null && info.getMacAddress() != null) { 
                        if (callback != null) { 
                            ac.runOnUiThread(new Runnable() { 
                                @Override 
                                public void run() { 
                                    callback.onComplete(info.getMacAddress()); 
                                } 
                            }); 
                        } 
                        return; 
                    } 
   
                    SystemClock.sleep(300); 
                    tryCount++; 
                } 
   
                // 未获取到mac地址 
                if (callback != null) { 
                    callback.onComplete(null); 
                } 
            } 
        }).start(); 
    }

public interface SimpleCallback { 
    void onComplete(String result); 
}